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Injecting a gas like methane onto a GCFID
Posted: Thu Sep 27, 2012 3:40 am
by seamoro
I have to setup a method for methane analysis. I must inject from a gas tight syringe the methane gas. I assume i cant just direct inject into normal gc injection port otherwise the gas would escape?
Re: Injecting a gas like methane onto a GCFID
Posted: Thu Sep 27, 2012 6:51 am
by Peter Apps
Where would it escape to ? A GC inlet has to be gas-tight in order to hold the head pressure that drives carrier gas through the column.
Peter
Re: Injecting a gas like methane onto a GCFID
Posted: Thu Sep 27, 2012 8:30 am
by Johnny Rod
Better to use a gas sampling valve, that way it goes into the carrier consitently, and you get considerably better precision.
Re: Injecting a gas like methane onto a GCFID
Posted: Thu Oct 04, 2012 10:19 am
by antonk
You can even sample a room air with gas-tight syringe and analyse methane produced by living organisms.
Just properly clean carrier gas and FID hydrogen from hydrocarbons.
Sampling valve is required for both high throughput and required high reproducibility.
Re: Injecting a gas like methane onto a GCFID
Posted: Wed May 29, 2013 10:39 am
by chromatographer1
Re: Injecting a gas like methane onto a GCFID
Posted: Tue Jun 04, 2013 8:23 am
by jdezeeuw
what detector will you use? What other components can be present?
This all determines what separation you need.
TCD will respond to everything, so you NEED a higher retention for methane. If A FID is used, and you have also C2-C3 there, you also need a xcolumn that separates the C2+ components from your methane.
j de zeeuw, Restek corporation